Methods of Magnetizing Permanent Magnets （磁化永久磁铁的方法）.PDFVIP

Methods of Magnetizing Permanent Magnets EMCW Coil Winding Show 1 October-2 November 2000 Cincinnati , Ohio Joseph J. Stupak Jr. Oersted Technology Corp. 19480 SW Mohave Ct. Tualatin, Oregon USA 97063 Tel (503) 612-9860 fax (503) 692-3518 email oersted@ Copyright Oersted Technology 2000 Methods of Magnetizing Permanent Magnets 1. Introduction Many people find magnets to be strange, mysterious things, and I think that physicists are puzzled a good deal more by them then they like to admit. Magnets have been with us a long time, in fact from our earliest history, long before formal science was started, or the mathematics we use to describe it. We all know what magnets do. Magnets have locations on them, called poles. Poles come in two types, which we call North-seeking poles, or just North poles, and South poles. They always occur in pairs of equal strength, although they may have more than just two poles, of course. Opposite pole types attract, while poles of the same type repel each other. Poles of either type attract iron, steel, and a few other metals such as nickel. These things have been known for thousands of years. Much more recently, that is in the last two hundred years, we have found out that electricity and magnetism are related, and most of the time today we will be talking about ways to use electricity to make certain special materials, called permanent magnet materials, to be magnetic. When magnets are first produced, they are usually not magnetic at all, or possibly they are only very weakly magnetic. For the magnet to have the properties we need, it must be magnetized. This can be done at the factory which first made the material, but for a number of reasons it usually is preferable to ship the parts in an unmagnetized state. The magnets are then either built into useful things like speakers, electric motors, generators, instruments, and such, and then magnetized in place, or else